.alpha.-cyanoacrylate adhesives have been widely used in not only various fields of industry but also the fields such as `do it yourself` and hobby handicrafts at home since they have many advantages, in addition to strong adhesion, such as fast setting time, handiness owing to lower viscosity, nonpollution owing to the discontainment of solvent and prevention of micropores from forming on the bond surface accompanied with the evaporation of solvents. On the other hand, it has been indicated that they are inferior in heat resistance. This disadvantage has been serious in the cases which the heat resistance is required, for example in bonding of articles, parts and the like prior to burning coating.
In order to improve such a disadvantage various methods are proposed. For example heat resistance of .alpha.-cyanoacrylate is tried to be strong by adding N,N'-substituted bis-maleimide compounds (Japanese Pat. Publication No. 11688/1977), maleic anhydride or derivatives thereof (Japanese Pat. Publication No. 12737/1977), isocyanate compounds or polyisocyanate compounds (Japanese Pat. Publication No. 19418/1979), hydroxyalkyl esters of .alpha.,.beta.-unsaturated carboxylic acids or hydroxyhalogenoalkyl esters of .alpha.,.beta.-unsaturated carboxylic acids (Japanese Pat. Laying-Open No. 110635/1978) and sulfone compounds and dicarboxylic acid anhydrides (Japanese Pat. Laying-Open No. 66980/1980) thereto, respectively.
However, such additives have been apt to prolong the setting time increasingly with the improvement in heat resistance in general. Since it goes without saying that the fast cure is the greatest characteristic of .alpha.-cyanoacrylate adhesives, the prolonged setting time damages the worth as instant adhesives. Although the heat resisting temperature can be increased to about 250.degree. C. at maximum according to the invention disclosed in Japanese Pat. Publication No. 11688/1977 cited at first, it is necessary to turn .alpha.-cyanoacrylate adhesives into prepregs or films prior to the use thereof. Therefore, they can no longer be called instant adhesives.
It is an object of the present invention to provide adhesives having remarkably improved heat resistance with holding the high cure speed suitable for instant adhesives.